Why do we want prices in healthcare?

A couple of days ago I fell to talking about price-setting in health care with a certified Very Smart Economist. Bart Wilson is the Donald P Kennedy Professor of Economics and Law at Chapman University, where he works with Vernon Smith, the chap who won the Nobel Prize for helping to invent experimental economics. We had both watched the same web video, where certified Very Smart Health Care Wonks Ezra Klein and Sarah Kliff argued... well, conversed... in favor of some sort of central rate setting to control health care costs.